Seat belts have been standard in vehicles for over fifty years as a safety measure to hold vehicle occupants in place during a quick deceleration or vehicle collision. In that time, additional innovations have been made in seat belt technology, such as the inclusion of locking retractors and pretensioning devices, to further enhance their safety benefits. For example, in the event of a vehicle collision, a pretensioning device will tighten the seat belt almost instantly to reduce motion of the occupant and to help stabilize the occupant in an optimum position within the seat.
Another innovation in seat belt technology includes the use of inflatable seat belts, for example to help distribute collision impact loads in frontal collision events. More specifically, in the event of a collision, a bladder within the seat belt webbing will inflate to increase a surface area that contacts the occupant, thereby spreading the forces pushing against the occupant. Inflation of the bladder also shortens the amount of seat belt tensioning necessary to tighten the belt around the occupant, thus providing a faster reaction time and further reducing unwanted motion of the occupant. Generally, these inflatable bladders are located within the seat belt to be positioned over the occupant's lap or across the occupant's chest.
The above innovations are very beneficial in frontal collision events, where they prevent forward movement and stabilize the occupant's torso against the seatback. However, these and other innovations do little to help stabilize the occupant's shoulders during a side or lateral collision. During a side impact, the most effective load paths through the occupant's body are through the shoulder and the pelvis. However, in the event of a such a side impact, the occupant's shoulder may rotate forward and away from the impact, shifting the impact load path from the shoulder to the more exposed thorax and abdominal areas. Therefore, there is a need for a method and apparatus for stabilizing the occupant's shoulder by restraining the shoulder so that it maintains its load carrying capability during side impact and provides for reduced risk of injury to an occupant's thorax and abdomen during a side collision.